Re: Advertising local host routes in BGP?

You tell me. Again, I don't fully understand what the problem is now.
I guess you have to reproduce the problem in a lab scenario before you
try to find a solution...

-Carlos

Jeffrey Pazahanick @ 20/04/2010 19:17 -0300 dixit:
> I don't have the FIB/RIB data from the actual failure; only from
> trying to find a way to advertise a host route in my lab..
> So bgp inject-map is off of the table?
>
> On Tue, Apr 20, 2010 at 10:48 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
>> Hmm, I don't know what the problem is. All the info you send now seems ok.
>> Can you provide a small configuration set that we can use to reproduce the
>> issue ?
>> If this is related to the doc you referred before, your FIB would be
>> inconsistent with your RIB, which is not the case in the provided
>> show ooutputs.
>>
>> -Carlos
>>
>> Jeffrey Pazahanick @ 20/4/2010 11:30 -0300 dixit:
>>> That doesn't seem to work either...
>>>
>>> ip route 1.1.1.5 255.255.255.255 1.1.1.5
>>>
>>>
>>> R1#sh ip cef 1.1.1.5 det
>>> 1.1.1.5/32, version 37, epoch 0
>>> 0 packets, 0 bytes
>>> via 1.1.1.5, 0 dependencies, recursive
>>> unresolved
>>>
>>> R1#sh arp
>>> Protocol Address Age (min) Hardware Addr Type Interface
>>> Internet 1.1.1.1 - 0015.fa64.6d21 ARPA
>>> FastEthernet0/1
>>> Internet 1.1.1.5 16 0015.fa64.7b13 ARPA
>>> FastEthernet0/1
>>> Internet 10.1.12.1 - 0015.fa64.6d20 ARPA
>>> FastEthernet0/0
>>> Internet 10.1.12.2 16 0015.fa64.7518 ARPA
>>> FastEthernet0/0
>>>
>>> R1#sh ip route 1.1.1.5
>>> Routing entry for 1.1.1.5/32
>>> Known via "static", distance 1, metric 0
>>> Advertised by bgp 1
>>> Routing Descriptor Blocks:
>>> * 1.1.1.5
>>> Route metric is 0, traffic share count is 1
>>>
>>> ----
>>>
>>> Remove the static.
>>>
>>> R1#conf t
>>> Enter configuration commands, one per line. End with CNTL/Z.
>>> R1(config)#no ip route 1.1.1.5 255.255.255.255 1.1.1.5
>>> R1(config)#^Z
>>> R1#ping
>>> *Apr 20 14:29:07.057: %SYS-5-CONFIG_I: Configured from console by console
>>> R1#ping 1.1.1.5
>>>
>>> Type escape sequence to abort.
>>> Sending 5, 100-byte ICMP Echos to 1.1.1.5, timeout is 2 seconds:
>>> !!!!!
>>> Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
>>> R1#sh ip cef 1.1.1.5 det
>>> 1.1.1.0/24, version 32, epoch 0, attached, connected
>>> 0 packets, 0 bytes
>>> via FastEthernet0/1, 0 dependencies
>>> valid glean adjacency
>>> R1#sh arp
>>> Protocol Address Age (min) Hardware Addr Type Interface
>>> Internet 1.1.1.1 - 0015.fa64.6d21 ARPA
>>> FastEthernet0/1
>>> Internet 1.1.1.5 19 0015.fa64.7b13 ARPA
>>> FastEthernet0/1
>>> Internet 10.1.12.1 - 0015.fa64.6d20 ARPA
>>> FastEthernet0/0
>>> Internet 10.1.12.2 19 0015.fa64.7518 ARPA
>>> FastEthernet0/0
>>> R1#sh ip route 1.1.1.5
>>> Routing entry for 1.1.1.0/24
>>> Known via "connected", distance 0, metric 0 (connected, via interface)
>>> Routing Descriptor Blocks:
>>> * directly connected, via FastEthernet0/1
>>> Route metric is 0, traffic share count is 1
>>>
>>>
>>> Any other suggestions?
>>>
>>> On Sat, Apr 17, 2010 at 6:57 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar>
>>> wrote:
>>>> Send it to the destination:
>>>>
>>>> ip route 1.1.1.5 255.255.255.255 1.1.1.5
>>>>
>>>> That worked in a couple of versions I tested it. I did no other test,
>>>> so I don't know if it fixes your issue, but it may help.
>>>>
>>>> -Carlos
>>>>
>>>>
>>>> Jeffrey Pazahanick @ 17/04/2010 1:33 -0300 dixit:
>>>>> Carlos,
>>>>>
>>>>> How do you have a static /32 pointed to the segment if you are the next
>>>>> hop?
>>>>>
>>>>> R1#conf t
>>>>> Enter configuration commands, one per line. End with CNTL/Z.
>>>>> R1(config)#ip route 1.1.1.5 255.255.255.255 1.1.1.1
>>>>> %Invalid next hop address (it's this router)
>>>>> R1(config)#R1#conf t
>>>>>
>>>>>
>>>>> On Fri, Apr 16, 2010 at 5:10 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar>
>>>>> wrote:
>>>>>> Interesting reading (the loop problem).
>>>>>> Caused by a floating static route to a multipoint if.
>>>>>>
>>>>>> You say:
>>>>>>> The link says the solution is to point the statics to the next hop;
>>>>>>> which I can't, as they are local.
>>>>>> which triggered me to try it. And it works.
>>>>>>
>>>>>> You can have a static /32 route to a next hop which is in a connected
>>>>>> segment. Which solves your need for a given /32 prefix to be published
>>>>>> by BGP w/o the burden of proxy ARP poisoning your CEF adjacency
>>>>>> table...
>>>>>>
>>>>>> -Carlos
>>>>>>
>>>>>>
>>>>>>
>>>>>> Jeffrey Pazahanick @ 16/04/2010 0:37 -0300 dixit:
>>>>>>> I have a situation where I'm trying to advertise only 4 host routes
>>>>>>> from a /24 network to my BGP neighbors.
>>>>>>> As an example,
>>>>>>>
>>>>>>> #R1
>>>>>>> interface g0/0
>>>>>>> ip addr 1.1.1.2 255.255.255.0
>>>>>>> standby ip 1.1.1.1
>>>>>>>
>>>>>>> router bgp 1
>>>>>>> network 1.1.1.4 mask 255.255.255.255
>>>>>>> network 1.1.1.5 mask 255.255.255.255
>>>>>>> network 1.1.1.7 mask 255.255.255.255
>>>>>>> network 1.1.1.9 mask 255.255.255.255
>>>>>>>
>>>>>>> With a single router, a static route to the interface worked fine..
>>>>>>>
>>>>>>> ip route 1.1.1.4 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.5 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.7 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.9 255.255.255.255 g0/0
>>>>>>>
>>>>>>> When adding a redundant router, things initially work as well..
>>>>>>>
>>>>>>> #R2
>>>>>>> interface g0/0
>>>>>>> ip addr 1.1.1.3 255.255.255.0
>>>>>>> standby ip 1.1.1.1
>>>>>>>
>>>>>>> router bgp 1
>>>>>>> network 1.1.1.4 mask 255.255.255.255
>>>>>>> network 1.1.1.5 mask 255.255.255.255
>>>>>>> network 1.1.1.7 mask 255.255.255.255
>>>>>>> network 1.1.1.9 mask 255.255.255.255
>>>>>>>
>>>>>>> ip route 1.1.1.4 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.5 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.7 255.255.255.255 g0/0
>>>>>>> ip route 1.1.1.9 255.255.255.255 g0/0
>>>>>>>
>>>>>>> The issue arises when R1 fails, R2 has a CEF routing loop..
>>>>>>>
>>>>>>> Troubleshooting Cisco Express Forwarding Routing Loops
>>>>>>> Document ID: 26083
>>>>>>>
>>>>>>> http://www.cisco.com/en/US/partner/tech/tk827/tk831/technologies_tech_note09186a00800cdf2e.shtml
>>>>>>>
>>>>>>> The link says the solution is to point the statics to the next hop;
>>>>>>> which I can't, as they are local.
>>>>>>>
>>>>>>> Is there another way to advertise these host routes?
>>>>>>>
>>>>>>> I've been trying to use inject-maps, but my own routers are the route
>>>>>>> source, and it doesn't appear to work.
>>>>>>>
>>>>>>> Ideas?
>>>>>>>
>>>>>>>
>>>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________________________________
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>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> --
>>>>>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>>>>>
>>>> --
>>>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>>>
>> --
>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net